JP7244388B2 - Quantum information processing device and quantum bit array - Google Patents

Description

The present invention relates to a quantum information processing device.

Currently, many groups around the world are conducting research aimed at realizing quantum computers. Experiments are being conducted in various physical systems, but regardless of which physical system is used, what is first required to realize a quantum computer is to create quantum bits in an isolated system that does not exchange matter or energy with the outside world, is to be able to maintain the coherence of

In order to operate qubits as a quantum computer, it is essential not only to pursue the performance of a single qubit, but also to construct a device that includes multiple qubits.

There are reports on multi-qubit semiconductor qubits (see Patent Document 1, for example), but this is a structure in which the structure of a single qubit is horizontally extended as it is. A large number of electrodes are arranged above and below, and the states of the qubits and interactions between qubits are controlled by DC voltages applied to them.

However, in this structure, as the number of qubits increases, so does the number of electrodes. When operating at cryogenic temperatures in a refrigerator, the number of electrodes to which a DC voltage or RF pulse can be applied from the outside is limited, and there is a limit to the number of qubits that can be increased.

In addition, the qubits are arranged in a one-dimensional straight line, but if the qubits are arranged in a two-dimensional plane with this structure, it cannot be realized because there is no place to arrange the control electrodes.

Thus, it is difficult to form a two-dimensional planar array of qubits by extending the qubit structure proposed so far. Nevertheless, it is widely recognized that a two-dimensional extension is necessary to make it work as a quantum computer. For this reason, proposals have been made for such a quantum bit string structure (see, for example, Patent Document 2). This is intended to individually control two-dimensionally extended qubit arrays by switching with wiring and transistors formed in the upper layer.

WO2009/072550 Japanese Patent Publication No. 2018-532255

However, in the structure of the quantum bit string of Patent Document 2, if a quantum bit with a complicated structure is formed in the lower layer, the crystallinity of the substrate cannot be maintained up to the upper layer. Therefore, it is difficult to form a transistor in the upper layer with the current semiconductor manufacturing method.

SUMMARY OF THE INVENTION It is an object of the present invention to enable qubits to be extended two-dimensionally in a quantum information processing device using current semiconductor manufacturing methods.

A quantum information processing device according to one embodiment of the present invention includes a quantum information processing device including a fin, a first layer provided over the fin, and a second layer provided over the first layer. The apparatus, wherein the fin includes a qubit array in which a plurality of qubits are aligned in a first direction and an interaction array in which a plurality of inter-qubit interactions are aligned in the first direction. wherein the qubit array and the interaction array are alternately arranged in a second direction different from the first direction, the first layer is arranged in the first direction, and the quantum a first gate electrode row that controls the qubits of the bit row, and a second gate electrode row that is arranged in the first direction and controls the interaction between the qubits of the interaction row, The second layer includes a third gate electrode row arranged in the second direction and a fourth gate electrode row arranged adjacent to the third gate electrode row in the second direction. and a part of the qubits among the plurality of qubits and a part of interactions between the plurality of qubits by the third gate electrode row and the fourth gate electrode row is characterized by controlling the inter-qubit interaction of each.

According to one aspect of the present invention, in a quantum information processing device, qubits can be made two-dimensionally scalable using current semiconductor manufacturing methods.

2 is a bird's-eye view of the structure of a quantum bit string that constitutes a quantum information processing device; 1 is a plan view of a quantum information processing device; FIG. 1 is a plan view of a quantum information processing device; FIG. It is a top view which shows the manufacturing method of the quantum bit string which comprises a quantum information processing apparatus. FIG. 4 is a cross-sectional view A showing a method of manufacturing a quantum bit string that constitutes a quantum information processing device; FIG. 2B is a cross-sectional view showing a method of manufacturing a quantum bit string that constitutes the quantum information processing device; It is a top view which shows the manufacturing method of the quantum bit string which comprises a quantum information processing apparatus. FIG. 4 is a cross-sectional view A showing a method of manufacturing a quantum bit string that constitutes a quantum information processing device; FIG. 2B is a cross-sectional view showing a method of manufacturing a quantum bit string that constitutes the quantum information processing device; It is a top view which shows the manufacturing method of the quantum bit string which comprises a quantum information processing apparatus. FIG. 4 is a cross-sectional view A showing a method of manufacturing a quantum bit string that constitutes a quantum information processing device; FIG. 2B is a cross-sectional view showing a method of manufacturing a quantum bit string that constitutes the quantum information processing device; It is a top view which shows the manufacturing method of the quantum bit string which comprises a quantum information processing apparatus. FIG. 4 is a cross-sectional view A showing a method of manufacturing a quantum bit string that constitutes a quantum information processing device; FIG. 2B is a cross-sectional view showing a method of manufacturing a quantum bit string that constitutes the quantum information processing device; It is a top view which shows the manufacturing method of the quantum bit string which comprises a quantum information processing apparatus. FIG. 4 is a cross-sectional view A showing a method of manufacturing a quantum bit string that constitutes a quantum information processing device; FIG. 2B is a cross-sectional view showing a method of manufacturing a quantum bit string that constitutes the quantum information processing device; It is a top view which shows the manufacturing method of the quantum bit string which comprises a quantum information processing apparatus. FIG. 4 is a cross-sectional view A showing a method of manufacturing a quantum bit string that constitutes a quantum information processing device; FIG. 2B is a cross-sectional view showing a method of manufacturing a quantum bit string that constitutes the quantum information processing device; It is a top view which shows the manufacturing method of the quantum bit string which comprises a quantum information processing apparatus. FIG. 4 is a cross-sectional view A showing a method of manufacturing a quantum bit string that constitutes a quantum information processing device; FIG. 2B is a cross-sectional view showing a method of manufacturing a quantum bit string that constitutes the quantum information processing device; It is a top view which shows the manufacturing method of the quantum bit string which comprises a quantum information processing apparatus. FIG. 4 is a cross-sectional view A showing a method of manufacturing a quantum bit string that constitutes a quantum information processing device; FIG. 2B is a cross-sectional view showing a method of manufacturing a quantum bit string that constitutes the quantum information processing device; FIG. 3 is a detailed cross-sectional view of a fin of a quantum bit that constitutes the quantum information processing device; FIG. 2 is a cross-sectional view of a quantum bit string and an electron energy level diagram for explaining a method of initializing a quantum bit string that constitutes a quantum information processing device; FIG. 2 is a cross-sectional view of a quantum bit string and an electron energy level diagram for explaining a method of performing a rotation gate operation in a quantum bit string constituting a quantum information processing device; FIG. 10 is a plan view of a quantum bit string for explaining individual operability when a rotation gate operation is performed in the quantum bit string constituting the quantum information processing device; FIG. 4A is a cross-sectional view of a quantum bit string and an electron energy level diagram for explaining a method of performing a control gate operation in a quantum bit string that constitutes a quantum information processing device; FIG. 4A is a cross-sectional view of a quantum bit string and an electron energy level diagram for explaining a method of performing a control gate operation in a quantum bit string that constitutes a quantum information processing device; FIG. 4 is a plan view of a quantum bit string for explaining individual operability when performing a controlled-NOT gate operation in the quantum bit string that constitutes the quantum information processing device; FIG. 4 is a plan view of a quantum bit string for explaining individual operability when performing controlled-NOT gate operations in the quantum bit string constituting the quantum information processing apparatus of the present invention; FIG. 2 is a cross-sectional view of a quantum bit string and an electron energy level diagram for explaining a method of reading out a quantum bit string that constitutes a quantum information processing device; FIG. 2 is a cross-sectional view of a quantum bit string and an electron energy level diagram for explaining a method of reading out a quantum bit string that constitutes the quantum information processing apparatus of the present invention;

Embodiments will be described below with reference to the drawings.
First, the structure of a quantum bit string that constitutes a quantum information processing device will be described.

As shown in FIG. 1, the qubit string has a five-layer structure. From the bottom, the first layer, the second layer, the third layer, the fourth layer, and the fifth layer. Each layer is insulated by a layer of insulator (eg SiO ₂ ).

The first layer is a semiconductor (eg, p-type Si) initialization gate 101 . A DC voltage can be applied to the entire surface of the second layer from the lower layer.

The second layer has fins 102 of semiconductor (eg, intrinsic Si). As shown in FIG. 2, a quantum bit 201 is formed in a two-dimensional square lattice on the upper surface of the fin 102 . Interactions 202 between the qubits are formed according to the shape of the fins 102 . The fins 102 are shaped so that all the qubits 201 interact in the horizontal direction and some of the qubits 201 interact in the vertical direction.

The third layer is divided into an upper layer and a lower layer, each of which has a semiconductor (eg, poly-Si) gate electrode. There are two types of gate electrodes, qubit control gates 103 and 105 and interaction control gates 104 and 106 . The lower layer has a straight gate electrode extending vertically, and quantum bit control gates 103 and interaction control gates 104 are alternately arranged. However, the gate electrode is not formed on the straight-shaped fin 102 extending in the horizontal direction in the second layer. The upper layer has a linear gate electrode extending horizontally, and quantum bit control gates 105 and interaction control gates 106 are alternately arranged. The qubit control gate 105 and the interaction control gate 106 in the upper layer are in contact with the fin 102 in the second layer in the portion where the gate electrode is not formed in the lower layer.

The fourth layer has conductors 107 of conductor (eg, Al). It has a straight shape extending horizontally.

The fifth layer has magnets 108 of ferromagnetic material (eg Co). The qubit 201 has a shape with different sizes extending in the horizontal direction so that different static magnetic fields are applied to the qubit 201 .

Electrodes are connected as shown in FIG. It is This makes it possible to apply a DC voltage or RF pulse, or to take out the output RF pulse. A switch 203 is provided outside the quantum bit string to switch input/output signals. Therefore, the number of terminals connected to the outside does not increase in proportion to the number of quantum bits 201 .

The number of qubits 201 can be extended horizontally and vertically to any number of columns. For example, in FIG. 2, 5 rows in the horizontal direction and 3 rows in the vertical direction, a total of 15 qubit rows are arranged. By repeating the same structure as in FIG. It is also possible to configure 6 strings, for a total of 60 qubit strings.

Next, a method for fabricating a quantum bit string will be described step by step.
As shown in FIGS. 4A, 4B, and 4C, an initialization gate 101 of semiconductor (eg, p-type Si formed by implanting impurities) is formed on the entire surface of a substrate of semiconductor (eg, crystalline Si). Initialization gate 101 is used to initialize quantum bit 201 . A layer 402 of insulator (eg, SiO ₂ ) is formed over the initialization gate 101 . A semiconductor (eg, crystalline Si) fin 102 is formed on a layer 402 of insulator. The shape of the fins 102 ultimately determines the coupling relationship between each qubit. In the horizontal direction, all columns are aligned, and in the vertical direction, some columns form bonds as needed. Finally, a gate insulating film 403 made of an insulator (for example, SiO ₂ ) is formed to insulate the fin 102 from the gate electrode to be formed thereafter.

A semiconductor (eg, poly-Si) qubit control gate 103 is formed over the fin 102, as shown in FIGS. 5A, 5B, and 5C. The qubit control gate 103 has a linear shape extending vertically. As a result, junctions with the quantum bit control gates 103 are discretely formed on the linear fins 102 extending in the horizontal direction, and by confining single electrons, the quantum bits 201 can operate. Become. An insulator (eg, Si ₃ N ₄ ) spacer 501 is formed on the qubit control gate 103 to insulate it from the subsequently formed gate electrode.

Interaction control gates 104 of semiconductor (eg, poly-Si) are formed between each qubit control gate 103, as shown in FIGS. 6A, 6B, and 6C. Similar to the quantum bit control gate 103, it has a linear shape extending in the vertical direction. As a result, junctions with the interaction control gates 104 are discretely formed on the linear fins 102 extending in the horizontal direction, and interactions 202 between the qubits 201 arranged in the horizontal direction can be controlled. become. After that, a layer 601 of insulator (eg SiO ₂ ) is formed and a planarization process is performed.

As shown in FIGS. 7A, 7B, and 7C, the gates are not discretely formed on the straight-shaped fins 102 extending in the vertical direction, so the quantum bit control gates 103 are formed by masking and etching back. to remove The gate insulating film 403 on the fin 102 is exposed again by adjusting the etching conditions so that the etch back stops on the gate insulating film 403 .

As shown in FIGS. 8A, 8B, and 8C, a semiconductor (eg, poly-Si) qubit control gate 105 is formed on a vertically extending straight-shaped fin 102 . Unlike the qubit control gate 103, this time it has a linear shape extending in the horizontal direction. Through this process, junctions with the quantum bit control gates 105 are discretely formed on the linear fins 102 extending in the vertical direction, and single electrons are confined so that they can operate as the quantum bits 201 . Become. A spacer 501 isolates it from the qubit control gate 103 and the interaction control gate 104 . An insulator (eg, Si ₃ N ₄ ) spacer 801 is formed on the qubit control gate 105 to insulate it from the subsequently formed gate electrode.

Interaction control gates 106 of semiconductor (eg, poly-Si) are formed between each qubit control gate 105, as shown in FIGS. 9A, 9B, and 9C. Similar to the quantum bit control gate 104, it has a linear shape extending in the horizontal direction. As a result, junctions with the interaction control gates 106 are discretely formed on the linear fins 102 extending in the vertical direction, and interactions 202 between the qubits 201 arranged in the vertical direction can be controlled. become. After that, a layer 901 of insulator (eg SiO ₂ ) is formed and a planarization process is performed.

As shown in FIGS. 10A, 10B, and 10C, a conductor (eg, Al) lead 107 is formed over the qubit control gate 105 and the interaction control gate 106 . Similar to the quantum bit control gate 103 and the interaction control gate 104, it has a linear shape extending in the horizontal direction. This allows RF pulses to be applied to qubit 201 . RF pulses of the same frequency and duration are applied to the qubits 201 arranged in the horizontal direction. After that, a layer 1001 of insulator (for example, SiO ₂ ) is formed and a planarization process is performed.

As shown in FIGS. 11A, 11B, and 11C, a magnet 108 made of a ferromagnetic material (for example, Co) is formed on a conducting wire 107 and magnetized. Although it has a shape extending in the horizontal direction, by continuously changing the width or thickness, each quantum bit 201 arranged in the horizontal direction is applied with a different static magnetic field. By the above method, a quantum bit array having the structure shown in FIG. 1 can be produced.

In this way, the quantum information processing device of the above embodiment includes the fin 102, the first layer provided on the fin 102, and the first layer provided on the first layer, as shown in FIG. 2 layers.

As shown in FIG. 2, the fin 102 includes a qubit row in which a plurality of qubits are arranged in a line in a first direction (for example, the vertical direction) and a plurality of qubits in the first direction (for example, the vertical direction). inter-qubit interactions are arranged in a row and the qubit row and the interaction row are in a second direction (e.g., horizontal) that differs from the first direction (e.g., vertical) are arranged alternately.

As shown in FIG. 1, the first layer includes a first row of gate electrodes (qubit control gates 103) arranged in a first direction (e.g., vertical) and controlling the qubits of the qubit row; and a second row of gate electrodes (interaction control gates 104) arranged in a first direction (eg, vertical direction) to control the inter-qubit interactions of the interaction row.

As shown in FIG. 1, the second layer comprises a third row of gate electrodes (qubit control gates 105) arranged in a second direction (eg, horizontal) and a third row of gate electrodes (qubit control gates 105) arranged in a second direction (eg, horizontal). ) and a fourth row of gate electrodes (interaction control gate 106) arranged adjacent to the third row of gate electrodes (qubit control gate 105).

A third gate electrode row (qubit control gate 105) and a fourth gate electrode row (interaction control gate 106) allow interaction between some of the plurality of qubits and the plurality of qubits. (see FIG. 2).

Here, in the second layer, the third gate electrode row (qubit control gate 105) and part of the fourth gate electrode row (interaction control gate 106) are arranged in the first direction (for example, vertically) (see FIG. 8B). This electrode array controls some of the qubits and some of the inter-qubit interactions (see FIG. 2).

As shown in FIGS. 2 and 3, for example, the electrode arrays are discretely provided in a second direction (for example, horizontal direction) so as to two-dimensionally expand the number of quantum bits.

Further, as shown in FIG. 8B, for example, the electrode array constitutes a protruding portion, and the protruding portion is in contact with the fin 102 . For example, the protruding portion is a portion of the first layer where the first gate electrode row (qubit control gate 103) and the second gate electrode row (interaction control gate 104) are not formed. touch.

According to the above embodiments, in a quantum information processing device, it is possible to extend the quantum bits two-dimensionally using current semiconductor manufacturing methods.
An embodiment will be described below with reference to the drawings.

In a first embodiment, a method of initializing a quantum bit string of a quantum information processing device will be described.

To enable initialization of the qubit 201, the fin 102 has a three-layer structure, as shown in FIG. In order from the bottom, the first layer 1201 is made of an n-type semiconductor (eg, n-type Si), the second layer 1202 is made of an insulator, and the third layer 1203 is made of a semiconductor (eg, intrinsic Si). The first layer 1201 is used as an electron reservoir.

FIG. 13 shows changes in the state of electrons when three qubits 201 arranged horizontally in the qubit string are extracted and initialized. The qubits 201 formed below the qubit control gates 1301, 1302, 1303 shown in the cross-sectional view of the qubit string in FIG. 13 are called qubits A, B, and C, respectively. Here, qubits A, B, and C are all initialized.

Shown at the bottom of FIG. 13 are the energy levels of the qubits A, B, C and the reservoir (not corresponding to the spatial arrangement of the qubits A, B, C and the reservoir).

Since a static magnetic field is applied to the qubits A, B, and C by the effect of the magnet 108, a difference in energy occurs between |↑> and |↓> due to Zeeman splitting. Furthermore, since the magnitudes of the static magnetic fields applied to the qubits A, B, and C are different, a gradient is formed in the energy difference between |↑> and |↓>.

Applying a positive DC voltage to the initialization gate 101 and applying a negative DC voltage to the qubit control gates 1301, 1302, 1303 causes electrons in the first layer 1201 of the fin 102 to cross over the second layer 1202 of the fin 102. to the junctions of the third layer 1203 of the fin 102 with the qubit control gates 1301 , 1302 , 1303 . When the DC voltage applied to the initialization gate 101 is returned to zero when one electron moves, the electron is confined in the junction of the third layer 1203 of the fin 102 with the qubit control gates 1301, 1302, 1303. , will act as qubits 201 . All electron spin states are |↓> with low energy. Since the qubit string is cooled to an extremely low temperature by the dilution refrigerator, it is hardly changed to |↑> by thermal energy. By the above method, all the quantum bits 201 are prepared in the |↓> state and can be initialized.

Although the reservoir is formed under the quantum bit in the first embodiment, it may be formed beside the quantum bit instead. In that case, the initialization gate 101 becomes unnecessary. All the qubits can be initialized by sending electrons sequentially from the edge of the qubit array to the inside.

In a second embodiment, a method of performing a rotation gate operation on a quantum bit string of a quantum information processing device will be described.

FIG. 14 shows changes in the state of electrons when rotating gate operations are performed by extracting three qubits 201 arranged in the horizontal direction in the qubit string. The qubits 201 formed below the qubit control gates 1301, 1302, 1303 shown in the upper cross-sectional view of the qubit string in FIG. 14 are called qubits A, B, and C, respectively. Here, qubits A and B perform rotation gate operations, respectively. The energy levels of qubits A, B, and C are shown at the bottom of FIG.

When an RF pulse is applied to conductor 107, all of the horizontally aligned qubits A, B, and C are RF pulsed. Then, when the energy difference between |↑> and |↓> matches the energy difference hν (h is Planck's constant) corresponding to the frequency ν of the RF pulse, rotation of the electron spin occurs. Rotation gate operation can be performed by the above method.

By controlling the magnitude and time width of the RF pulse, rotation gate operation of any magnitude can be performed. For example, adding an RF pulse corresponding to phase π results in a NOT gate operation.

The individual operability of rotating gate operation will be described with reference to FIG.
Since the energy difference between |↑> and |↓> of the qubits 201 arranged in the horizontal direction is different, the rotation gate operation can be performed on any qubit 201 in the qubit string. For vertically aligned qubits 201, the conductors 107 are physically separated so that RF pulses can be selectively applied. As a result, any quantum bit 201 in the quantum bit string can be manipulated.

In Example 2, the magnet 108 is used to change the energy difference between the qubits (by the Zeeman effect), but the energy difference can be changed by changing the voltage applied to the qubit control gate (by the Stark effect). may In that case, the magnet 108 becomes unnecessary.

Further, although the RF pulse is applied through the conductor 107 in the second embodiment, the RF pulse may be applied through the qubit control gate 103 . In that case, the conducting wire 107 becomes unnecessary.

In a third embodiment, a method of performing a controlled NOT gate operation in a quantum bit string of a quantum information processing device will be described.

16 and 17 show changes in the state of electrons when the controlled NOT gate operation is performed by extracting three qubits 201 arranged in the horizontal direction in the qubit string.

The qubits 201 formed below the qubit control gates 1301, 1302, 1303 shown in the cross-sectional views of the qubit arrays in the upper part of FIG. 16 and the upper part of FIG. 17 are called qubits A, B, C, respectively. Here, the controlled NOT gate operation is performed with the quantum bit A as the target bit and the quantum bit B as the control bit. The energy levels of qubits A, B, and C are shown at the bottom of FIG. 16 and at the bottom of FIG.

FIG. 16 shows the electronic state change when a NOT gate operation occurs at the target bit because the control bit is |↑>. Although the electron energies of the target bit and the control bit are drawn separately in (1), the electron energies of the target bit and the control bit can also be drawn together as in (2). (1) and (2) are equivalent. It has the highest energy when both electrons are |↑>, and the lowest energy when both electrons are |↓>. When the respective electron spins are antiparallel, an intermediate value is obtained. There is also an energy difference between and |↓↑>.

(3) shows the state of electrons when the controlled NOT gate operation is performed. Interaction between the target bit and the control bit Applying a negative DC voltage to the control gate 104 lowers the energy because the respective electron spins are stable when antiparallel. Therefore, the energy difference between |↑↑> and |↑↓> can be adjusted to any value by the magnitude of the DC voltage applied to the interaction control gate 104 .

After setting the energy difference between |↑↑> and |↓↑> to a value larger than the energy difference between combinations of other electron states, an RF pulse having a frequency ν corresponding to the energy difference hν is passed through the conductor 107. Add. Then, electron spin rotation occurs between |↑↑> and |↓↑>. When the DC voltage applied to the interaction control gate 104 is returned to zero after the RF pulse corresponding to the phase π is applied, the state in which the target bit is subjected to the NOT gate operation as shown in (4).

FIG. 17 shows the change in electron state when the target bit does not undergo a NOT gating operation because the control bit is |↓>. The only difference from FIG. 16 is that the state of the first control bit is |↓> instead of |↑>, and there is no difference in the applied DC voltage or RF pulse. However, since the states |↑↑> and |↓↑> do not exist in (2) and (3), electron spin rotation does not occur. Controlled NOT gate operation can be performed by the above method.

The individual operability of the controlled NOT gate operation will be described with reference to FIGS. 18 and 19. FIG. FIG. 18 shows the case where target bits and control bits are aligned horizontally. The interaction control gates 104 are horizontally spaced while the conductors 107 are vertically spaced and the state of the electrons will not change unless the respective DC voltage and RF pulse are applied simultaneously. Therefore, a controlled NOT gate operation can be performed on any two adjacent qubits 201 in the qubit string. Also, by changing the magnitude of the DC voltage applied to the interaction control gate 104, it is possible to select which of the two qubits 201 that are aligned to be the target bit or the control bit.

FIG. 19 shows the case where target bits and control bits are aligned vertically. Both interaction control gates 104 and conductors 107 are vertically separated, so that two horizontally aligned qubits 201 are subjected to the controlled NOT gate operation at the same time.

In a fourth embodiment, a method of reading out a quantum bit string of a quantum information processing device will be described.

FIGS. 20 and 21 show changes in the state of electrons during readout of three qubits 201 arranged horizontally in the qubit string. Let the qubits 201 formed under the qubit control gates 1301, 1302, 1303 shown in the cross-sectional views of the qubit strings in the upper part of FIG. 20 and the upper part of FIG. 21 be qubits A, B, C, respectively. Here, qubit C is used as a readout control bit, and qubit B is used as a qubit to be measured.

FIG. 20 shows changes in electron states when the state of the quantum bit B to be measured is |↑>. As shown in (2), by applying a negative DC voltage to the interaction control gate 104 between qubit B and qubit C, the energy barrier between the two qubits is lowered, and the qubit control gate Increasing the negative DC voltage applied to 1303 encourages the transfer of electrons from qubit B to qubit C. Since the electron state of the qubit B is |↑> and the electron state of the qubit C is |↓>, the Paulis spin blockade does not occur, and electron transfer occurs. When the DC voltage applied to interaction control gate 104 is then returned to zero, qubit C confines two electrons.

FIG. 21 shows changes in electron states when the state of the quantum bit B to be measured is |↓>. If the same operation as in FIG. 20 is performed, electron transfer from qubit B to qubit C is promoted. No electron transfer occurs. After that, when the DC voltage applied to the interaction control gate 104 is returned to zero, one electron is confined in the qubit C. FIG.

In both cases of FIGS. 20 and 21, an RF pulse is finally applied to the quantum bit control gate 103. FIG. Since the impedance differs between the case of one electron and the case of two electrons, the number of electrons in qubit C can be estimated by examining the phase of the reflected RF pulse. state can be measured. The read operation can be performed by the above method.

Since all qubits 201 have the same structure, any qubit in the qubit string may be used for reading. However, since the qubit control gates 103 and 105 have a linear shape extending in the vertical or horizontal direction, reading is performed for all qubits 201 aligned in the direction of the qubit control gate 103 or the qubit control gate 105. are performed at the same time.

It should be noted that the present invention is not limited to the above embodiments, and includes various modifications. For example, the positional relationship between the first qubit control gate and the second qubit control gate may be any angle instead of vertical. In that case, for example, a triangular lattice or a hexagonal lattice can be configured instead of a two-dimensional square lattice. Also, the number of layers of the qubit control gate and the interaction control gate may be three layers or more instead of two layers. In that case, interactions between qubits can occur not only in horizontal and vertical directions, but also in arbitrary angular directions.

Reference Signs List 101 Initialization gate 102 Fin 103 Qubit control gate 104 Interaction control gate 105 Qubit control gate 106 Interaction control gate 107 Lead wire 108 Magnet 201 Qubit 202 Interaction 203 Switch 401 Semiconductor crystal substrate 402 Insulator layer 403 Gate insulating film 501 Spacer 601 Insulator layer 801 Spacer 901 Insulator layer 1001 Insulator layer 1201 N-type semiconductor layer 1202 Insulator layer 1203 semiconductor layer 1301 quantum bit control gate 1302 quantum bit control gate 1303 quantum bit control gate

Claims (14)

fins and
a first layer overlying the fin;
A quantum information processing device having a second layer provided on the first layer,
The first layer is
a first row of gate electrodes extending in a first direction and controlling the qubits ;
a second gate electrode row that extends in the first direction and controls interaction between qubits ;
The second layer is
a third gate electrode row extending in a second direction different from the first direction ;
a fourth gate electrode row extending in the second direction and arranged adjacent to the third gate electrode row;
Some of the plurality of qubits or some of the plurality of interactions between the qubits by the third gate electrode array or the fourth gate electrode array A quantum information processing device characterized by controlling The second layer is
parts of the third gate electrode row and the fourth gate electrode row extend in the first direction as electrode rows;
2. The quantum information processing apparatus according to claim 1, wherein the electrode array controls the part of the qubits and the interaction between the part of the qubits. The electrode row is
3. The quantum information processing apparatus according to claim 2, wherein the quantum bits are provided discretely in the second direction so as to expand the number of the quantum bits two-dimensionally. The electrode row constitutes a protrusion,
3. The quantum information processing device according to claim 2, wherein the protrusion is in contact with the fin. The protrusion is
5. The quantum information processing device according to claim 4, wherein a portion of said first layer where said first gate electrode row and said second gate electrode row are not formed is in contact with said fin. 2. The quantum information processing device according to claim 1 , further comprising a conductor array provided on said second layer and extending in said second direction for applying a high frequency signal to said quantum bit. . 7. A quantum information processing apparatus according to claim 6, further comprising a magnet array provided on said conductor array and extending in said second direction for applying a static magnetic field to said quantum bit. 2. The quantum information processing device according to claim 1, further comprising an initialization gate electrode under said fin for initializing said quantum bit. 2. The quantum information processing apparatus according to claim 1, wherein said first direction and said second direction are directions that cross each other. 10. A quantum information processing apparatus according to claim 9, wherein said first direction is vertical and said second direction is horizontal. The electrode row is
3. The quantum information processing device according to claim 2, wherein a plurality of quantum information processing devices are provided in the second direction. fins and
a first layer overlying the fin;
A quantum information processing device having a second layer provided on the first layer,
The fins are
a qubit string in which a plurality of qubits are arranged in a line in a first direction;
an interaction array in which a plurality of inter-qubit interactions are arranged in a row in the first direction;
the qubit array and the interaction array are alternately arranged in a second direction different from the first direction;
The first layer is
a first gate electrode array arranged in the first direction and controlling the qubits of the qubit array;
a second gate electrode array arranged in the first direction and controlling the inter-qubit interaction of the interaction array;
The second layer is
a third gate electrode row arranged in the second direction;
a fourth gate electrode row arranged adjacent to the third gate electrode row in the second direction;
interaction between some of the plurality of qubits and interaction between some of the plurality of qubits by the third gate electrode array and the fourth gate electrode array; A quantum information processing device characterized by controlling actions respectively. fins and
a first layer overlying the fin;
A quantum information processing device having a second layer provided on the first layer,
The first layer is
a first row of gate electrodes extending in a first direction and controlling the qubits;
a second gate electrode row that extends in the first direction and controls interaction between qubits;
The second layer is
a third gate electrode row extending in a second direction different from the first direction;
a fourth gate electrode row extending in the second direction and arranged adjacent to the third gate electrode row;
A quantum information processing device according to claim 1, wherein a part of the third gate electrode row and the fourth gate electrode row has a protrusion, and the protrusion is in contact with the fin. fins and
a first layer overlying the fin;
A qubit array having a second layer provided on the first layer,
The first layer is
a first row of gate electrodes extending in a first direction and controlling the qubits;
a second gate electrode row that extends in the first direction and controls interaction between qubits;
The second layer is
a third gate electrode row extending in a second direction different from the first direction;
a fourth gate electrode row extending in the second direction and arranged adjacent to the third gate electrode row;
Some of the plurality of qubits or some of the plurality of interactions between the qubits by the third gate electrode array or the fourth gate electrode array A quantum bit array characterized by controlling

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